Hjerim

Hjerim is the house that that player can purchase in Windhelm. It features prominently in the quest Blood on the Ice. The "Cleanup" addition removes the stone altar, bloody chest, and blood and bones on the floor that are found there during the quest.

WARNING Having the house cleaned before finishing Blood on the Ice can break that quest. (The murderer from that quest will be stuck inside your house, he is hostile, immortal, and can't be pickpocketed and may take a weapon from your house)

There are numerous bugs associated with this house/quest line i.e., weapon racks/mounts cannot be activated.

There is a possibility that if you do not initially choose the option to clean up the murderer's mess, it will go away and you will be stuck with a room full of blood and bones. In addition, after paying for the arcane enchanter and the alchemy station, they will not show up.